1. Field of the Invention
The present invention relates to a Venetian blind and more specifically to a cord member control device for use in the bottom rail of a Venetian blind to support a corresponding lift cord and a corresponding ladder tape.
2. Description of the Related Art
FIG. 12 shows a conventional Venetian blind 90, which comprises a headrail 91, a plurality of slats 92, a bottom rail 93, two ladders 94, and two lift cords 95. The headrail 91 is transversely fixedly mounted in the top side of the window. The slats 92 are arranged in parallel below the headrail 91, each having two through holes 96 near the two distal ends. The ladder tapes 94 join the slats 92 between the headrail 91 and the bottom rail 93, each comprised of a front tape 941, a rear tape 942 and a plurality of retaining straps connected between the front tape 941 and rear tape 942 at different elevations to hold the slats 92 in parallel between the headrail 91 and the bottom rail 93. The front tape 941 and the rear tape 942 of the ladder type 94 are fastened to the bottom side of the bottom rail 93 with a plug member 97, which supports a guide roller 98 inside the bottom rail 93. Each lift cord 95 has one end fixedly fastened to the headrail 91, and the other end downwardly inserted through one through hole 96 of each slat 92 and moved over the guide roller 98 at the corresponding plug member 97 and then upwardly inserted through the same through hole 96 in each slat 97 to the headrail 91 and then extended out of one end of the headrail 91 for operation by the user to lift and lower the bottom rail 93. The guide roller 98 enables the user to operate the lift cord 95 with less effort.
This design of the above-mentioned Venetian blind 90 is functional. However, it is inconvenient to adjust the vertical length of the Venetian blind 90 in order to fit a relatively smaller window. When adjusting the vertical length of the Venetian blind 90, the user must remove the unnecessary slats 92 and cut off the unnecessary part of the ladder tapes 94, and then remove the plug members 97 and the waste parts of the ladder tapes from the bottom rail 93, and then fasten the plug members 97 to the bottom rail 93 to secure the front tapes 941 and rear tapes 942 of the ladder tapes 94 to the bottom rail 93. The guide roller 98 at each plug member 97 enables the user to pull the respective lift cord 95 with less effort; however, this design is still not satisfactory in function. Further, because each slat 92 must have through holes 96 for the passing of the lift cords 95, incident light may pass through the through holes 96 into the inside of the house when the user tilted the slats 92 to the close position.